Device for making shoe lasts by profile milling



1953 H. .WERKLUND 2,648,357

DEVICE FOR MAKING SHOE LASTS BY PROFILE MILLING Filed Dec. 13, 1948 2 Sheets-Sheet l Aug. 11, 1953 H. WERKLUND 2,648,357

DEVICE FOR MAKING SHOE LASTS BY PROFILE MILLING Filed Dec. 15, 1948 i 2 Sheets-Sheet 2 Patented Aug. 11, 1953 DEVICE FOR MAKING SHOE LASTS BY PROFILE MILLING Harald Werklund, Simrishamn, Sweden, assignor to A B Svenska Skolastfabriken, Jarrestad,

Sweden Application December 13, 1948', Serial No. 65,026 In Sweden December 18, 1947 3 Claims. (Cl. 142-15) This invention relates to a device for optionally varying" the heel and toe heights when profile milling shoe lasts in a so-called last-turning lathe andwill be described more in detail in the following, reference being had to the accompanying drawings, in which Fig. 1 shows a shoe last arranged in natural position on a horizontal plane.

Fig. 2'showstwo' uniform shoe lasts of different sizes in a similar manner.

Fig. 3 is'a front view'of a last-turning lathe provided with a 'deviceaccording to the invention.

Fig. 4 shows'the same lathe, as seen from above.

Fig. 5 is an axial section of the embodiment of the invention, used in the lathe according to Figs. 3 and 4.

Fig. 6 shows a'detail of an automatic control device, and Fig. 7 shows a cross-sectional view taken along line VII-VII in Fig. 5;

A'usual shoe last consists, as seen from Fig. 1,

of a toe portion 5, an instep portion 2 and a heelportion 3.

When the last is arranged'in natural position on a horizontal plane 4, the underside of the heel portion 3 is at its rear at a certain heightk over the plane 4. This height is called the heel height, because it corresponds to the necessary height of the heel of the shoe to be manufactured with the aidof the last. The front end of the under side of the'toe portion is at a-c'ertain height'over the plane i, and this height is called the toe height. There is no certain relation between the heel and toe heights, but quite generally it may be said that for each heel height there is a certain toe height which is best suited for the appearance of the shoe model in question.

Shoe lasts are usually manufactured in a large series of sizes or numbers by profile milling in a so-called last-'turning-lathe, in which a model or template and one or more last blanks are rotatable about axes of rotation extending longitudinally of the model and the last blank or blanks, respectively. The model is manufactured by hand by a relatively well paid last-modeller. The model is made in the so-called model size,which is generallythe most usual size, 1. e. fora mans last No. 42, fora ladys last No. 37. Bigger and smaller-size numbers of the last form in question are made with the aid of the same model by enlargement or reduction during the profile milling operation by means of a pantograph mechanism.

Such an enlargement or reduction is disadvantageous owing to the fact that in this type of operation the last isexe'cuted uniformlywith respect to themodel using.- the identical dimensions and relationships. Actually in this type of operation both the heel and, toe heights vary in'size relatively to the model, as appears from Fig. 2, in which on the one hand the model 5 is shown with its heel height 7c and toe height t and on the otherhand a last 6 copies by profile milling and by" enlargement from the model is shown and arranged on the same reference plane 1, so that it will readily be seen that in the enlarged last copy millimeters the manufacturer wants to have thisheel height not only in the model number 37'but also in all other sizes from e. g. No. 34lup to No.

41. For a heel height of millimeters the most suitable toe height is about 7 millimeters, and this toe height is therefore desired in all size numbers within the number series in question.

In order to meet these requirements it has been proposed that when profile milling shoe lasts in a last-turning lathe the model shall be swung relative to its axis of rotation in one or more stages of the milling of the last-blank or blanks. This swinging movement may take place automatically and at a determined speed, but also half-automatically and at varying swinging speeds forobtaining the desired corrections. The automatic swinging should be used as a rule when producing whole number series of lasts, i. e. in the production of'lasts, and the half-automatic swinging when producing new models having considerably diverging heel and toe heights.

The present invention relates to an improved device for automatically or half-automatically swinging the model in relation to its axis of rotation during the last turning operation. A preferred embodiment of the invention is shown by way of example in Figs; 3 to 6 of the accompanying drawings and will now be describedin detail.

Referring to Figs. 3 and i, the last-turning lathe is of a known construction comprising a Moreover, a headstock l2 and a tailstock l3-for clamping two last blanks i l and !5 are mounted on the frame 8. The spindles of the headstocks 9 and I2 are driven in a known manner by a motor (not shown) enclosed in the frame 8 through a drive shaft it. It should be observed that the two spindles of the headstock l2 are rotated in opposite directions for obtaining a right-foot last and a left-foot last. As appears from Figs. 3 and 4 the model II and the last blanks l4 and I5 are each clamped at the toe and the heel, so as to rotate about a longitudinal axis.

A tracer having the form of a roll [1, is mounted on a longitudinally reciprocating arm l8 disposed on a carriage l9 displaceable on the frame 8 in parallel with the axes of rotation of the model and the last blanks. An arm 29 is longitudinally movable on the carriage l9 and carries a milling cutter 2|, corresponding to the tracer roll H, for each of the last blanks l4, IS, the said arm 26 being mechanically coupled with the arm [8 by means of a pantograph mechanism so as to be reciprocated in a determined relation to the reciprocating movements of the arm I8. Furthermore the known pantograph mechanism is so constructed that the movements of the milling cutters 2| parallel to the axes of rotation of the last blanks are in a normally fixed, but alternatively adjustable relation to the movements of the tracer roll I! parallel to the axis of rotation of the model ll. By suitable adjustment of the pantograph mechanism it is thus possible to mill the last blanks l4 and I5 bigger or smaller than the model II, as desired.

To attain the above-mentioned relative swinging movement between the model H and the axis of rotation thereof during the profile milling operation there is used in the embodiment shown in Figs. 3 to '7 a mechanism which appears best from Figs. 5 and '7. On the spindle 22 of the headstock 9 there is fixed a body portion 23 forming a guide for a holder 24 for fixing the model II. The holder 24 is guided by a curved guide groove in the body portion 23 having side and front members 25 and 25a, respectively, and a bottom wall 23 against which the end of the holder 24 is applied. The holder 24 is movable along the guide means 25, 25a and 26 approximately at right angles to the axis of rotation of the spindle 22, but the guide means are somewhat curved with their centre of curvature situated on the means 2! (Fig. 3) for fixing the end of the last model M, supported by the tailstock I0, so that the model is safely clamped without any play when moving the holder 24. At each side of the holder 24 nuts 28 extend between the guide members 25a. The said nuts 28 are in engagement with a screw 29 extending freely through a hole 36 provided in the holder 24. At the ends of the guide means 25, 25a, 26 the screw 29 is J'ournalled in bearings 3| on the body portion 23 so as to be rotatable but not displaceable. When rotating the screw 29 the holder 24 is displaced along the guide means 25, 25a, 23 by the nuts 28. The axis of rotation of the model coincides in the drawings with the center axis of the spindles 22 and 21 and in the embodiment shown it is always fixed in relation to the machine frame, whereas during the rotation the model itself can be pivoted about its point of suspension on the spindle 21 by moving the member 24- along the guide 25 so that the model occupies different angular positions in relation to its axis of rotation, i. e. the center axis of the spindles 22 and 21.

At its one end the screw 2.9 has a bevel gear 32 engaging with a bevel gear 33 attached to one end of a shaft 34 mounted in. the body 1901?" tion 23 in parallel with and spaced from the axis of rotation of the body portion 23, determined by the spindle 22. The other end of the shaft 34 carries a planet gear 35 engaging with a sun gear 36 which is freely rotatably mounted on the body portion 23 coaxially with the axis of rotation thereof.

On the frame of the headstock 9 there is fixed a sleeve 31 surrounding the spindle 22 and the portion of the member 23 passed on to the spindle. The sleeve 31 has mounted thereon a brake means or a clutch disc 38 having coupling teeth 39 (or a frictional covering) for engagement with corresponding coupling teeth 4i! (or a frictional covering) provided on the sun gear 35 freely rotatable on the body portion 23. The clutch disc 38 is non-rotatably but axially movably mounted on the sleeve 31 when the model II is to be automatically swung in relation to its axis of rotation, and is rotatable and axially movable on the sleeve 31, when the model I l is to be half-automatically swung in relation to its axis of rotation by manual control of the disc Normally the clutch disc 33 is at a distance from the sun gear 36 which will therefore rotate together with the body portion 23 during the rotation of the body portion by means of the spindle 22, because the said gear is actuated by the planet gear 35. Thus, the screw 29 will thereby be at a standstill relatively to its bearings, so that the holder 24 is retained in adjusted position. However, if the clutch disc 33 is moved towards the sun gear 36, so that the coupling teeth 39 and 40 are engaged, the clutch disc, when held against rotation, will retain the sun gear 36 stationary relatively to the frame of the lathe, while the body portion 23 is rotated by the spindle 22. Thereby the planet gear 35 will roll against the sun gear 36, so that the bevel gears 32, 33 are rotated and in turn rotate the screw 29, whereby the holder 24 is moved along the guide means 25, 25a and 26. Thus, the model II is swung about the fixing means 27 of the tailstock l0, whereby a relative swinging movement is obtained between the model and its axis of rotation for the purpose aimed at.

The swinging of model I l in relation to its axis of rotation should be effected during the milling of the instep portion of the last, and in the embodiment shown this swinging movement is effected automatically or by hand. The automatic swinging movement is realized by means of a control device comprising a rod 42 mounted below the model II in a bearing 4| (see Figs. 3 and 4) on the frame 8 of the lathe so as to be movable parallel to the axis of rotation of the spindle 22. The said rod 42 is connected by means of a transverse rod 43 (Fig. 4) in the frame 8 to the carriage l9, so that it is reciprocated together with the arm l8 and the tracer roll 11. A plate 44 (see also Fig. 6) extending upwards from the rod 42 is exchangeably attached to the end of said last-mentioned rod. In a certain position of the rod 42 and thus of the tracer roll I1 the plate 44 comes into contact with a transverse arm 45 on a shaft 46 which is journalled in bearings 41 on the frame of the headstock 9. At its upper end the shaft 46 has two sidewardly extending arms 48 engaging in a groove 49 provided in the clutch disc 38 (see also Fig. 5). Between the bearings 41 a helical spring 50 is wound around the shaft. One end of said spring is fastened to the shaft 46 and the other end of the spring is fastened to the upper bearing 41 so When, during the displacement of the rod 42'' together with the tracer roll! I, the plate 34 con-' tacts the arm 45-and continues its movement, the" arm 45 is swung by the plate M- so that, theshaft ifi-is-rotated in such a way that the arms 48- mo-ve'the clutch disc 38 into engagement with the gear 36, the screw 29 displacing the holder 24 in the above manner. The arm at rides against the surface of the plate 44 during passage of the arm by the plate and after the plate 44 has passed the arm 35 completely the helical spring 50 returns the clutch disc as to its inactive position in which it is out of engagement with the gear 36, whereby the displacement of the holder 24 is stopped. The plate M is preferably attached to the rod 42 in such a position, that the displacement of the holder 2t takes place during milling of the instep portion of the last, and the plate 44 should be of such a length longitudinally of the rod 42 that the swinging, necessary for the last in question, of its axis of rotation H in relation to the model is obtained. Since this swinging movement must be different for different last numbers, the plate M has to be replaced by a plate of another length, when another last number is to be milled with the aid of the model I l. Sometimes it may be desirable to divide the necessary relative swinging movement between the model M and its axis of rotation into two steps that are taken during the milling of different portions of the last, and in doing so it is of course possible to arrange two 1 plates 44 of suitable dimensions at desired points along the length of the rod t2.

Of course, the invention must not be considered as limited to the embodiment described above and shown in the drawings, for several modifications may be made without going outside the scope of the invention. It may be pointed out especially that it is possible to dispose a swinging device 23 to 50 both at the heel and the toe of the model M, or the swinging device may be disposed at the toe instead of at the heel.

What I claim and desire to secure by Letters Patent is:

1. A device for supporting one end of a shoe last from a spindle in a last-turning lathe, comprising a body portion supported by said spindle, a sun gear mounted for rotation around the axis of said spindle on said body portion, a planet gear rotatably mounted on said body portion and meshing with said sun gear, a first bevel gear connected to said planet gear and rotatable thereby, a shaft rotatably mounted on said body portion and extending substantially at right angles to the axis of said spindle, a second bevel gear fixed to said shaft and meshing with said first bevel gear, guiding means on said body portion extending along said shaft, screw thread means on said shaft, a holder for said end of the shoe last, nut means on said shaft engaging said screw thread means, said guiding means partially surrounding and engaging said holder and said nut means to prevent rotation of said holder and nut means around the axis of said shaft, when said shaft is rotated, and gu d Said 11010191 and nut means along said shaft, when said nut means are screwed along said shaft during rotation of said shaft, and means mounted on the frame of the lathe and axially movable to engage said sun gear to prevent rotation thereof and to causea relative rotation ofsaid sun gearin rela tionto said 'bodyportion, when said body portionis-rotated togetherwith thelast, in order=to cause rota-ti on of said planetgear, said bevel gears "and said shaft for shifting said holder and nut means alongssaid shaft during the last-turningopera-- tion.

.2, A device for supportingoneend of ashoe last from a first spindle in a last-turning lathe, the other end of saidlast being pivotally connected to a second spindle in the lathe, comprising a body portion supported by said first spindle, a sun gear mounted for rotation around the axis of said first spindle on said body portion, a planet gear rotatably mounted on said body portion and meshing with said sun gear, a first bevel gear connected to said planet gear and rotatable thereby, a shaft rotatably mounted on said body portion and extending substantially at right angles to the axis of said first spindle, a second bevel gear fixed to said shaft and meshing with said first bevel gear, guiding means on said body portion extending along said shaft, said guiding means being curved with the axis of curvature at right angles to said first spindle and substantially coinciding with the pivot axis for said other end of the last, screw thread means on said shaft, holder means for said one end of the last, nut means on said shaft engaging said screw thread means on said shaft, said guiding means partially surrounding and engaging said holder means and nut means to prevent rotation of said holder means and nut means around the axis of said shaft, when said shaft is rotated, and guiding said holder means and nut means along said shaft, when said nut means are screwed along said shaft during rotation of said shaft, for swinging said one end of the last around the pivot axis for said other end of the last while, due to the curvature of said guiding means, maintaining said holder means on a constant distance from said second spindle, and means mounted on the frame of the lathe and axially movable to engage said sun gear to prevent rotation thereof and to cause a relative rotation of said sun gear in relation to said body portion, when said body portion is rotated together with the last, in order to cause rotation of said planet gear, said bevel gears and said shaft for shifting said holder means and nut means along said shaft during the last turning operation.

3. A device for supporting one end of a shoe last from a spindle in a last-turning lathe, comprising a body portion supported by said spindle, a sun gear mounted for rotation around the axis of said spindle on said body portion, a planet gear rotatably mounted on said body portion and meshing with said sun gear, a first bevel gear connected to said planet gear and rotatable thereby, a shaft rotatably mounted on said body portion and extending substantially at right angles to the axis of said spindle, a second bevel gear fixed to said shaft and meshing with said first bevel gear, guiding means on said body portion extending along said shaft, screw thread means on said shaft, holder means for said end of the shoe last, nut means on said shaft engaging said screw thread means on said shaft, said guiding means partially surrounding and engaging said holder means and nut means to prevent rotation of said holder means and nut means around the axis of said shaft, when said shaft is rotated, and guiding said holder means and nut means along said shaft, when said nut means are screwed along said shaft during rotation of said shaft, and brake means mounted on the frame of the lathe and axially movable to engage said sun gear to lock it against rotation together with said body portion in order to cause rotation of said planet gear, said bevel gears and said shaft, for shifting said holder means and nut means along said shaft, when said body portion is rotated together with the last during the last turning operation.

' HARALD WERKLUND.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Whipple Dec. 14, 1920 Boynton Jan. 10, 1922 Loewer Mar. 21, 1922 Reed Feb. 21, 1928 Clausing Apr. 18, 1939 Scott Mar. 16, 1943, 

